On the next stand was a Britannia 767 off-loading. It was packed. They'd come out directly from the U.K. in 26 hours with only a refuel in the Gulf.
Not so. The B767 needed 2 stops between UK and Oz. The first was in the Gulf, initially Bahrain, then Abu Dhabi, finally Sharjah. The second was initially Singapore, later Bataam just across the strait.
They were utterly, totally shattered, like zombies, poor little kids crying, wives and girl-friends wailing, they looked like walking wounded coming out of a war zone, but they said it had been a good flight.
Your description of pax condition on disembarking does not tally with what I saw. I operated a number of these flights, and remember happy but tired people on arrival in Oz. The Oz flights ran for a decade or so, chartered by Austravel, and ended when scheduled fares came down so much that the ticket prices had to fall, and the route became only marginally profitable. The commercial risk was too great: one major tech delay down-route would have wiped out the profit for the whole series of flights.